Related papers: The Decay Sigma^+ -> p l^+ l^- within the Standard…
We present a calculation of the rare decay mode D^0 -> gamma gamma, in which the long distance contributions are expected to be dominant. Using the Heavy Quark Chiral Perturbation Theory Lagrangian with a strong g coupling as recently…
We analyze data on $B\to K\mu^+\mu^-$ and $B\to K^*\mu^+\mu^-$ decays in the whole dilepton invariant mass spectrum with the aim of disentangling short- vs. long-distance contributions. The sizable long-distance amplitudes from $c \bar{c}$…
A search for the decay $B_{s}^0 \rightarrow \overline{K}{}^{*0}\mu^+\mu^-$ is presented using data sets corresponding to 1.0, 2.0 and 1.6 $\text{fb}^{-1}$ of integrated luminosity collected during $pp$ collisions with the LHCb experiment at…
The exclusive (B -> K_2 l^+ l^-) decay is studied using the most general, model independent four-fermion interaction. The sensitivity of the ratio of the decay widths when K_2 meson is longitudinally and transversally polarized, the…
Motivated by new precise results on several $K_L$ decays, sensitive to the ${K_L \to \gamma \gamma}$ form factor, we present a new analysis of the $K_L\to \mu^+\mu^-$ long-distance amplitude based on a semi-phenomenological approach.…
Studies of rare decays play an important role in the search of physics beyond the standard model. New particles may participate in the loop processes and can be probed by seeing any deviations from the standard model predictions. The very…
Inspired by various updated tantalizing results of LHCb on baryonic sector we study the {\Lambda}_b decays into {\Lambda}^* (1520)l^+ l^- decay in non-universal Z^' model. We present the four-fold angular distributions of the decay in terms…
Within the framework of the QCD sum rules, we consider the three-point correlation function, work at the limit q^2 -> 0 and m_\pi -> 0, and pick out the singular term ~ {1\over q^2} to extract the pionic coupling constants of the 1^{-+}…
We carry out a detailed study of the branching fractions and lepton pair invariant-mass spectrum of \tau^- ->\pi^- \nu_\tau l^+l^- decays (l=e,\mu). In addition to the model-independent (QED) contributions, we include the…
We present first calculations of new long-distance contributions to $B_s \to \gamma \gamma$ decay due to intermediate $D_s$ and $D_s^*$ meson states. The relevant $\gamma$ vertices are estimated using charge couplings and transition moment…
The short-distance Hamiltonian describing b->s(d)e^-e^+ in the standard model is used to obtain the decay spectrum of \bar{B}->K^-pi^+e^-e^+ and \bar{B}->pi^-pi^+e^-e^+, assuming the Kpi and pipi systems to be the decay products of K^* and…
TThe LHCb collaboration has recently reported evidence for non-zero CP asymmetries in $B^+$ decays into $\pi^+ K^+ K^-,\; \pi^+\pi^+\pi^-,\; K^+ K^+ K^- $ and $K^+\pi^+\pi^-$. The branching ratios for these decays have also been measured…
The radiative B -> tau^+ tau^- gamma decay is investigated in the framework of the Standard Model. When only short (short and long together) distance contributions are taken into account, the Branching Ratio is found as 9.54x10^(-9)…
We perform a theoretical analysis of the semileptonic decays $\eta^{(\prime)} \to \pi^0 \ell^+ \ell^-$ and $\eta' \to \eta \ell^+ \ell^-$, where $\ell = e, \mu$, via a charge-conjugation-conserving two-photon mechanism. The underlying form…
Following updated and extended measurements of the full angular distribution of the decay $\Lambda_b\to \Lambda(\to p\,\pi^-)\mu^+\mu^-$ by the LHCb collaborations, as well as a new measurement of the $\Lambda \to p \pi^-$ decay asymmetry…
The dependence of the T-odd correlation on the effective Lagrangian parameters in the $K^+ \to \pi l \nu \gamma, l=e, \mu$ decays is analyzed. It is shown that the introduced observable is perspective in a search for new physics in the…
The rare Bc->Ds l^+ l^- decay is investigated by using the most general model independent effective Hamiltonian. The general expressions of longitudinal, normal and transversal polarization asymmetries for l^- and l^+ and the combined…
The CP-violating asymmetries in the exclusive decay B->K^*l^+l^- (l=e,mu,tau) are predicted to be exceedingly small in the standard model (SM), thereby offering an opportunity to assess various new-physics scenarios. We derive quantitative…
A new evaluation of the charged Higgs boson decay $H^+ -> W^+\gamma$ is presented in the context of the general two-Higgs doublet model. A nonlinear $R_\xi$-gauge which considerably simplifies the calculation is introduced and simple…
Measuring the muon anomalous magnetic moment g-2 and the rare decays of light pseudoscalar mesons into lepton pair P \to l+l- serve as important test of the standard model. To reduce the theoretical uncertainty in the standard model…